HEF4521B - NXP

HEF4521B 24-stage frequency divider and oscillator

The HEF4521B consists of a chain of 24 toggle flip-flops with an overriding asynchronous master reset input (MR), and an input circuit that allows three modes of operation. The single inverting stage (I2/O2) will function as a crystal oscillator, or in combination with I1 as an RC oscillator, or as an input buffer for an external oscillator. Low-power HEF45.

Features

tly the HEF4521B will count up to 224 = 16777216. The counting advances on the HIGH to LOW transition of the clock (I2). The outputs of the last seven stages are available for additional flexibility. Fig.1 Functional diagram. FAMILY DATA, IDD LIMITS category MSI See Family Specifications January 1995 2 Philips Semiconductors Product specification 24-stage frequency divider and oscillator COUNT CAPACITY HEF4521B MSI OUTPUT O18 O19 O20 O21 Fig.2 Pinning diagram. O22 O23 O24 HEF4521BP(N): 16-lead DIL; plastic (SOT38-1) HEF4521BD(F): 16-lead DIL; ceramic (cerdip) (SOT74) HEF4521BT(D): 16-l.